Overheating

[Brian]

When I had my heads done (6 months after buying my BRA289 Rover 3.5)I discovered it had been running without a thermostat!Ages to heat up etc. Should have been a bit suspicious but who trusts gauges? Anyway put one in (pre-tested 82C ) it runs hot, take it out and it runs 20C cooler! Why? Airlock in top hose not able to be cleared by reduced flow through stat?( top hose does loop up and then down to rad.)Any suggestions? If it is likely to be air how do you clear it as hose is difficult to re-route.

[daxv8man]

Hi Brian
You don't say if you have a flexilble rubber hose with filler in hose or a metal
fixed hose? If you have a rubber top hose and you have a filler, Lift hose up as far as it will go and if you have a filler cap you will see the water level drop ,then top up.Did you leave the heater on hot when you drained the system?
if not you should have otherwise an air leak will develop. A simple way to try
to get rid of the air leak is to back flow, know this sounds crazy but it worked on mine, take cap of expansion tank (when water is cold) place your mouth over the expansion tank (make sure you have your filler cap of your top hose) and blow as hard as you can, this might take a few blows you should see air bubbles out of thru top hose, yes i know you are saying "are you sure", well
if you cant get your moth over the expansion tank , ask the wife.You also did not say what your temp is , mine goes up to 100dg then drops to 80 my normal
temp. I hope this is usefull to you ,however I'm sure other guys will come up with other answers.

HAPPY BLASTING GD

[Brian]

Thanks.Top hose is rubber with no filler in it. Can't remember if heater was open (pathetic).Maybe I need to fit a section of metal tubing in the top hose with a vent/filler in it - as it seems to be the highest part of the cooling system. Heat goes up to 100 whereas before it was only 85ish - you dont say why the stat made a difference? (- as this was the only variable)

[RigMan]

Sometimes these thermostats open but not wide enough. Therfore they act as a restriction and may be the reason your motor runs 20 degrees hotter with it in. Either order another one or talk to one of the engine suppliers who may be able to offer some advice/recomendations.

RigMan